# THE MARCELLUS SHALE GAS PLAY Geology, Development, and Water

- Resource Impact Mitigation

John H. Williams

https://profile.usgs.gov/jhwillia/ 

### New York Water Science Center Troy, New YorkMarcellus shale play is located in the Appalachian basin and covers parts of New York, Pennsylvania, Maryland, and West Virginia

Marcellus shale play is the one of three overlapping shale plays that includes the older Utica shale and the younger Devonian shalesLash and Engelder (2009) Union Springs Cherry Valley Oatka CreekHigh gammaradiationHigh gammaradiation Geophysical Log



## Marcellus Stratigraphy

Onondaga

MarcellusLash and Engelder (2009) Union Springs Cherry Valley Oatka CreekHigh gammaradiationHigh gammaradiation Geophysical Log



## Marcellus StratigraphyDarker gray = more organic rich

Smith (2010)



### Highest TOC (up to 20%)

## Seismic survey from Otsego County

Gamma log

Seismic image courtesy of GastemLash and Engelder , 2009

## Shale Gas Development

• First commercial gas well in the United States was a Devonian shale gas well drilled in 1821 near Fredonia, NY

Site of first gas well in the United StatesHydraulic Fracturing and Horizontal Drilling

4,000 ft3,000–8,000 ft 

## Marcellus Shale Gas Development

Source: Independent Oil and Gas Association of Pennsylvania

## Hydraulic Fracturing

• First hydraulic fracturing of oil & gas well was in 1948

• Medina Sandstone, a tight gas reservoir, was extensively

fraced in western New York and Pennsylvania during the 1970s

• 100,000 oil & gas wells are fraced per year

## Horizontal Drilling

• First horizontal well was drilled in 1948

• First horizontal shale gas well was drilled in 1988 in the Antrim Shale, Michigan

• First horizontal gas well in New York was

drilled in 1989 Trenton/Black River wellHorizontal Drilling

at Multi

- Well Pad Sites in Black Shale

4,000 ft3,000–8,000ft 

## Marcellus Shale Gas DevelopmentOrthogonal joint sets

East

- northeast trending J1

fractures and northwest

trending J2 fractures

Drill horizontal wells to the

north

- northwest or south

southeast perpendicular to major horizontal stress and

J1 fractures Dual porosity gas reservoir where fractures drain rapidly and matrix drain slowly

Connect matrix porosity to the wellbore by intersecting multiple J1 fractures

Free gas and adsorbed gas in matrix

Terry Engelder PSU

## Multi

- Well Drilling Pad Site

With Six Horizontal Laterals

Horizontal Lateral

## Multi

- Well Drilling Pad Site

With Six Horizontal Laterals

Horizontal Lateral



## Minimizes surface disturbance but concentrates industrial activity

### Directional rig for drilling horizontal leg Top

- set rig for drilling vertical

surface

- and intermediate

cased interval

### Walking legs on directional drilling rig Wellheads of first two of six

horizontal wells

~15 ftTeff ( 2011) 

### Horizontal wells target basal Marcellus Shale

### Target horizon (Union Springs Shale) mapped using offset well logs and seismic

Logging

- while

- drilling used to steer lateral within target beds

Schlumberger (2010) Gamma

DensityTompkins County, NY 

### High TOC and elevated radioactivity

in basal Marcellus Shale

Levanthal and others (1981)

### Uranium & Thorium to Radium & Radon Radioactive Decay Series

Radioisotope and half lifeDrill Core Sample Analysis

Lash and Engelder (2009) Gamma Log 

### High TOC and abundant pyrite in basal Marcellus Shale• Elevated uranium and abundant pyrite in high

- TOC black shale

• Multi

- horizontal well site will generate more than 500 times the volume

of shale cuttings than single

- vertical well site 

## Drill Cuttings

Core of target interval Drill cuttings

### Lined pit

Mixed with sawdust Closed

- loop system

Offsite disposal in landfill 

## Drilling Fluids and Cuttings4,000 ft3,000–8,000ft 

## Marcellus Shale Gas Development

Multi

- Stage High

- Volume Hydraulic Fracturing of Horizontal Laterals

### 3 to 5 million gallons of water for hydraulic fracturing of each horizontal lateral

## Typical Components of Frac Fluid

. • For a 3 million gallon frac job, the 0.5 percent is equivalent to 15,000 gallons of “chemistry”

• Re

- fracing may be needed due to proppant crushing, scale, etc.

## Infill Drilling Refrac

Devonenergy.com 

## Barnett Shale

## Water Withdrawals for Frac Water

• Water

- availability

issues are seasonal in

nature

• Withdrawal of 5 MGD

during high water insignificant, during low

water exceeds 10 percent of flow

• If surface water becomes more restrictive, industry will look to groundwater

• Surface

- water

withdrawals and municipal supply in PA

• Surface water and groundwater

– a single

resource • Cumulative impacts of multiple withdrawalsChloride (mg/L)

0 20,000 40,000 60,000 80,000 100,000 120,000

1 2 3 Total dissolved solids (mg/L)

0 50,000 100,000 150,000 200,000 250,000

1 2 3

Gross Alpha (pCi/L)

0 5000 10000 15000 20000

1 2 3 Barium (mg/L)

0 2500 5000 7500 10000

1 2 3

Water quality of flowback (1.5 million gallons) from Marcellus shale well after completion of hydraulic fracturing (Samples were taken at 1, 2, and 3 third intervals of the 2

- week flowback period, PADEP) 1,160

22 19,000

668 6,100 8,730 18,600 80,500 109,000

34,600 134,000 192,000

## TDS and Radioactivity of Flowback Water

### Uranium & Thorium to Radium & Radon Radioactive Decay Series

Radioisotope and half life

Brine from a Marcellus Shale

- Gas Well

Gross Alpha 20,800 pCi /L Gross Beta 2,390 pCi /L
Radium 226 10,200 pCi /L
Radium 228 1,250 pCi /L

Thorium 228 47.5 pCi /L

Thorium 232 0.0 pCi /L

Uranium 234 0.5 pCi /LReuse flowback

, onsite treatment for

solids / blend with 70 % freshwater Municipal wastewater treatment

plants not designed to handle

flowback chemistry

Limited number of disposal

wells in Ohio

### Microseismic Monitoring of Hydraulic Fracturing• Produces readily detectable microseismic events (400 per frac )

• Frac half lengths greater than 1,000 feet

• Frac azimuths typically east

- northeast parallel to J1 joint sets

• Reactivation of pre

- existing joints by strike

- slip failure 

### Marcellus Hydraulic Fracturing

Joint sets in the Appalachian Basin Microseismic for five Marcellus laterals Duncan and Williams

- Stroud (2009)1000 5 00

3500

4 000

4 5 00

5000

5500

6 000

Modified from Kostelnick (2010) Upper Hamilton Group 

## Stratigraphy and Frac BarriersMarcellus shale

Onondaga limestone Tully limestone

Upper Hamilton shale(Marcellus SPE 131783) 

## Microseismic Monitoring

of Marcellus FracsFisher ( 2010) 

## Microseismic Mapped Frac Tops and Bottoms

Marcellus ShaleSharma and others ( 2003) 

## Fracing near faultsTrenton Salt Marcellus

Utica Lockport Onondaga 

### Seismic Line from South

- Central New York

Smith ( 2010) TullyTeff ( 2011) 

### Avoid Structures

## Valley

- Fill Aquifers

Saturated deposits of glacial sand and gravel

### Fractured zone in Catskill Formation 

## Upper Devonian Fractured

- Bedrock AquifersBraun and others ( 2011) 

### Bedding fracture and joint in Lock Haven Formation 

## Upper Devonian Fractured

- Bedrock Aquifers

### Depth of Water Wells in USGS and NYSDEC Databases

South

- Central New York

### Water Wells that Penetrated Saltwater in South

- Central New York

Modified from Williams ( 2011)

### Water Wells that Penetrated Saltwater in North

- Central Pennsylvania

Williams and others (1998)344 588 7,800

40

10 13

2.1 0.2 36

NS 30

3.1 

### Water Quality of Typical Freshwater and Salty Water Wells in Upper Devonian Bedrock

Salty water wells (Williams and others, 1998) 3 4,600

304 Tioga County, PA

### Depth of Freshwater Zones Penetrated by Gas Wells

South

- Central New YorkModified from Williams ( 2011) 

### Wells that Penetrated Gas above the Marcellus Shale

South Central New York

### Freshwater and Gas in Close Vertical Proximity

### Methane in Water Wells

Marcellus/Utica Gas

- Play Area

Osborn and others ( 2011) Sampling sitesFRESH WATER AQUIFER ZONE

SHALLOW PRODUCING ZONE

INTERMEDIATE PRODUCING ZONE CONDUCTOR PIPE

SURFACE CASING

PRODUCTION CASING 

## Good Zonal Isolation

TARGET PRODUCING ZONE

## Poor Zonal Isolation

PRESSURE

BUILDS UP CONDUCTOR PIPE

SURFACE CASING

PRODUCTION CASING FRESH WATER AQUIFER ZONE

SHALLOW PRODUCING ZONE

INTERMEDIATE PRODUCING ZONE

TARGET PRODUCING ZONECASINGCEMENTFORMATION2,500

– 4,000 feet

Characterization of deep freshwater and shallow gas and saltwater Engineered zonal isolation by multiple casings, cement, packers, and venting 

## Protection of Freshwater AquiferFreshwater

Transition

Saltwater 

## Geophysical Logs and Base of Freshwater Aquifer

Log data courtesy of Shell Appalachia• Cemented surface casing may not be deep enough to protect freshwater aquifer

• Open annulus interval between top of production casing cement to bottom of surface casing may allow upward migration of salty water and gas

• Drilling and frac fluid storage in surface impoundments and burial of drill cuttings onsite may contaminant shallow groundwater and surface water

• One

- time use of frac fluid wasteful of

freshwater resources and creates disposal

issue 

### Shale Gas Development

Typical past practices

- 500 feet

Top of cement

2,750 ft

• No water

- well sampling before drilling/hydraulic fracturing operation• Surface casing/cement deep enough to protect freshwater aquifers 

### Shale Gas Development

Best practices based on state

- of

- the

- art technology and science

• Cement

- bond logging and pressure

testing to ensure good seals

• Water

- well sampling before and after drilling/hydraulic fracturing operation • Microseismic monitoring of hydraulic fracs • Drilling and frac fluid storage in tanks and offsite burial of drill cuttings

• Reuse of frac fluid reduces freshwater resource impacts and disposal issue • Intermediate and production casing/cement/packers to prevent upward migration of salty water and gas • Geophysical logging to delineate base of freshwater aquifers

• Avoid hydraulic fracturing near structures